Improved electrochemical performance of zinc oxide coated lithium manganese silicate electrode for lithium-ion batteries

ZnO-coated Li2MnSiO4/C composites have been successfully prepared by a preliminary formation of Li2MnSiO4/C by facile sol-gel method and a following coating process with ZnO via a wet chemical process. Phase compositions and morphology of the products have been investigated by XRD, SEM, TEM and EDX. The physical characterizations manifest that nano-layer ZnO has been successfully coated on the Li2MnSiO4 particle surface. Among the samples, 1 wt% ZnO coated Li2MnSiO4/C shows the best performance with an initial discharge capacity of 183 mAh g−1 at 0.1C rate and the specific capacities of 142 and 134 mAh g−1 at the high rate of 0.5C and 1C, respectively, which is much better than Li2MnSiO4/C without coating ZnO. The better electrochemical performance can be attributed to the significantly decrease of the charge transfer resistance and improvement of lithium ion diffusion coefficient after coating ZnO, which is beneficial for the rapid insertion/extraction of lithium ions.